1. Field of the Invention
The invention relates to a coupler, especially a forward coupler.
2. Related Technology
Electronic measuring instruments for microwave technology must generally be designed to provide a very broad bandwidth in order to cover all possible customer applications. For example, the lower frequency limit is about 10 MHz with an upper frequency limit, for example, about 60 GHz. The generation and processing of such a frequency range is split up internally into several meaningful sub-ranges. The sub-ranges must be combined with one another at the front panel connector. This can be achieved in many different ways. From the point of view of providing the lowest possible losses of level, 3 dB forward couplers have proved to be the best solution.
For example, U.S. Pat. No. 5,055,807 B1 discloses such a forward coupler. However, the disadvantage here is that the forward coupler disclosed incurs high manufacturing costs and, moreover, a connection of this coupler to other circuits is difficult.